Long‐term growth patterns in a pond‐dwelling population of crucian carp, Carassius carassius: environmental and density‐related factors

Abstract

Scale samples from crucian carp, Carassius carassius (L.), collected over a 10-year period from a population in an ornamental pond were used to examine patterns in growth as a function of environmental factors, including water temperatures. Back-calculated standard lengths (SL) at age differed between year classes in most cases. Annual SL increments were related to temperature and age using a non-linear growth model. Growth declined with increasing age, whereas annual SL increments increased with increasing water temperature. The best-fit model was with the total number of summer days when air temperature exceeded 20°C (using water temperature equivalents of air temperature). A growth model including water temperature, age, year class, relative condition and rainfall was a better fit than other models. Year-class strength was positively correlated with water degree-days, and year-class strength negatively affected annual SL increments. The results indicate that within a strong year class of crucian carp, the growth of individual fish is reduced compared with weak year classes, suggesting that density negatively affects growth in ponds where resources are limited. K E Y W O R D S : conservation, native species, non-linear growth, water temperature.

A review and meta‐analysis of growth and life‐history traits of a declining European freshwater fish, crucian carp Carassius carassius

“…If the disagreement continued, then the sample was excluded from further analysis – this occurred in <5% of all scale samples. As the validity of age estimates was successfully accomplished in several previous studies on crucian carp in the UK including some populations currently studied (Tarkan et al ., , ; Copp et al ., ), it was not repeated in the present study. The total scale radius and the radius of annual increments were measured from the focus to the posterior edge along the antero‐posterior axis.…”

“…Despite the long tradition of angling for crucian carp in the UK and the species' threatened status in England (Sayer et al ., ), very limited information was available on the species' demography (Marlborough, ) until recently (Copp et al ., , ; Tarkan et al ., , ). The present review reveals that crucian carp growth and reproductive traits vary considerably in all European countries for which data are available (Table , Figure ), with specimens up to 3 kg weight apparently present in the eastern part of the Baltic Sea (Anonymous, pers.…”

“…Effective conservation requires a good knowledge of the environmental biology of a species, in particular those traits that demonstrate considerable plasticity in response to local environmental conditions (Mann, ), such as growth and reproduction in crucian carp (Holopainen et al ., ; Szczerbowski et al ., ; Copp et al ., , ; Tarkan et al ., , ). At the local scale, in pond populations in which crucian carp reproduction is delayed and/or where growth rate and body condition are low, habitat rehabilitation efforts may be appropriate to facilitate revitalization of the existing populations.…”

“…However, from a scientific perspective, crucian carp has been the subject of extensive research in Finland during the 1980s and 1990s (Holopainen and Pitkänen, ; Holopainen and Ikari, ). In England, this fish species began to attract increased scientific interest (Wheeler, ; Copp et al ., , ; Tarkan et al ., , ) after pharyngeal bones from a Roman archaeological site in Southwark (London) were identified as crucian carp by A.C. Wheeler (Jones, ; Newdick, 1979). Crucian carp was subsequently considered by some as a species native to the UK (Wheeler, ) but not by others (Maitland, ), and genetic studies of crucian carp are currently under way to address this issue.…”

Towards the conservation of crucian carp Carassius carassius: understanding the extent and causes of decline within part of its native English range

“…A subsequent validation phase included 19 ponds of an adjacent area (with minimal overlap) between 29 March 2010 and 1 April 2010. Fishes were captured mainly by fyke netting, a method known to be effective in ponds for capturing C. carassius (Copp et al, 2008;Tarkan et al, 2011). Where possible, double-ended fyke nets were set perpendicular to the bank or to beds of aquatic vegetation and exposed overnight (for c. 16 h), with the number of fyke nets set being proportional to pond size.…”